Hi,I have got a rover lawnmower with this engine on it 129802-2025-B1.It stopped while I was cutting really long grass gave a backfire.It wouldn't start again cutting the story short I had to take head off lap in the vales set the correct valve clearance and put it all back together.If primed it will start with first pull of the cord every time and I have used for over an hour.The thing I hope you can help me with is this, occasionally it will slow down and I hear a few tapps/knock and then it picks up again has anyone any idea what this is?
Briggs and stratton 5.5
- Thread starter Andysp
- Start date
Make a video of this sound. Upload to youtube. Link it here so we can watch it and listen.
Auto Doc's
Lawn Addict
It appears you are overloading the engine while trying to cut grass that is too tall and or thick.
Auto Doc's
Lawn Addict
That sound reminds me of a bad spark plug or there is water in the fuel.
Auto Doc's
Lawn Addict
The soundbite in the video was very short, but it favored ignition misfire popping
sgkent
Lawn Addict
What others said ^^^
If I had to guess, that is a mis-fire and the pop pop pop is the mis-fire charge igniting in the muffler, from the next time it fires. It is a small muffler so it is a higher pitched sound than a bigger more resonant muffler. I would replace the spark plug with a new one from a local engine shop, Napa, or Autozone etc AND NOT from online. Use NGK, Briggs or Champion. Do not use Torch. If that doesn't get it, inspect the plug wire for chaffing, and double check the clearance between the coil and flywheel. It is possible it is something else like a little water in the fuel.
If I had to guess, that is a mis-fire and the pop pop pop is the mis-fire charge igniting in the muffler, from the next time it fires. It is a small muffler so it is a higher pitched sound than a bigger more resonant muffler. I would replace the spark plug with a new one from a local engine shop, Napa, or Autozone etc AND NOT from online. Use NGK, Briggs or Champion. Do not use Torch. If that doesn't get it, inspect the plug wire for chaffing, and double check the clearance between the coil and flywheel. It is possible it is something else like a little water in the fuel.